Unfortunate that the PDF links giving critical driver specs are broken - this does not inspire confidence about the rest of the company, or the quality of the webmasters they hire. How hard would it have been to have listed a few basic specs (Fs, Qts, Mms, Vas, normalized efficiency, Xmax, and price) as well as the marketese?

Hi Lynn,

None of the links are broken, the files just simply do not exist yet. I am one person and just simply can't keep up with everything. The person doing all design for drivers, sourcing all parts, designing and building all equipment, building all tooling, answering all emails and phone calls, doing the website, taking product pictures, etc is all just me. I have one person assembling and testing drivers (every driver made gets parameters tested) and one person part time to help with order processing and accounting.

The basic info, FS, Qts, Vas, Z, 1W SPL and Pe have all been listed. Xmax should be listed, but was not built into the back end by the designer. There are 4 highlights for every driver. For the TD15M the highlights listed state:
Pro Style Bass-Mid or bass horn
PVA Hand Coated Cloth Edge
Very Light, Stiff, Hand Coated and Sealed Paper Cone
6mm peak xmax, 40Hz~2Khz, 97dB@1w, 8ohm only

Quote:

Originally posted by apassgear I wouldn't use a foam surround speaker

Quote:

Originally posted by apassgear

First and most important factor is that foam degrades rapidly, say 8/10 years. I've had in the past Focals and Dynaudio which after this period of time were unusable.

And secondly if they degrade this fast the TS parameters
wont hold long.

my $0.02

Quote:

Originally posted by CLS Foam surround molds. It's the main reason it rots.

In where I live, foam surrounds without treatments usually survive for only 3~5 years because the damp and warm weather. Most people use their speakers with grilles on all the time. So, when they discover the rotted surrounds, it's already too late.

However this can be cured (well, mostly). I have 2 foam surround EV woofers. I applied a thin layer of silicon oil on the surrounds and it turns out very good after 12.5 years. I don't know if the whole compliance drifts or not. At least they still look and touch like new after more than twice of average life span. I'm pleased by such result.

There are 2 types of foam surrounds. The older foams are polyester foams and the newer are polyether. Polyester used to have issues with foam rot but are cheaper, have less issues with resonance, and have better elongation. The new polyether foams are more expensive but are much better with regards to environment. They are affected much less by UV rays, air, and moisture.

Now, from the experience of Lambda in the past and myself, the best of both worlds is to use a coated and sealed polyester surround. We apply 2 coats of damping material on the back side of every surround. The first is a sealer coat that soaks into the foam. This further damps any kind of resonance the surround may have and fully seals it from any air and moisture. The second application coats it further to protect more from the environment, UV rays, and again further damps the resonance. The front of the surround as well as the entire cone also gets 2 applications of a damping material. This is sprayed on with a cup gun for even coverage and to get a more attractive look than hand application. The entire front of the driver is then protected from UV rays, sealed from any air, and sealed from moisture.

I have only been building the drivers for about 4 years now, but have yet to have any with issues. Many people even put the IB15's using the same cone/surround in wet crawl spaces under homes in damp climates but have not had issues. From my knowledge, none of the drivers originally sold by Lambda back as far as 2000-2001 have had issues with foam rot.

Quote:

Originally posted by JoshK

I agree that their website is lacking. Some of the wanted information is in their forum, some in marketing mailer emails and some from past archives when they made them earlier.

They don't even show all model #'s of the Lambda's they said (in the mailer) they'll be making. For instance they make a 10" version of the TDM and I have 15" versions of the TDX's.

It isn't a lot different than GPA IMO. You have to mail them to get any information as it wasn't really on their site.

I had Bill at millersound recone a pair of my TDX's that got damaged and he mentioned in all his years working with pro audio woofers he'd never seen anything like these (size of motor, etc). He asked if they cost close to a grand each.

Any info that is required can easily be requested by email. I get multiple emails per day requesting this info. I'd love to provide the full PDF files, however it is VERY time consuming. I need to be able to measure response curves, impedance curves, distortion, put together 2-3 recommended enclosures for each driver, edit up mechanical drawings, etc. This is why I chose to put the basic parameters up on the site for now, Fs, Qts, Vas, nominal impedance, 1W SPL, and i commented in the highlights for Xmax on all the Lambda drivers as that wasn't in the list of parameters.

The fact is there are just too many models to list right now. I'd spend a week doing nothing but putting up parameters. The Dipole, TDS, TDX, TDH, and TDM are all available in 10", 12", and 15" sizes. Most all of those have 2-5 different impedance options to choose from as well.

Regarding the question if they cost close to a grand each, many people can't believe the cost of these drivers. We have had people swapping out TAD15's to replace them with TD15M's. Many find it difficult to believe how a 2" coil driver can be powered with 500W with little or no power compression, and how the 2" coil with Apollo option can run at 130+dB all night long in live music venues. I can tell you that the TD15's we sell at $279 would have to sell for between $500 to $1000 if they went through the traditional distribution-retailer-end user method, instead of direct to end user sales. We build ever driver to order with currently a 5 business day lead time and every driver is played for a short period and tested prior to being packaged to ship.

Quote:

Originally posted by Sheldon

Planet 10 can probably direct you to an archive site that shows the spec's for the Lambda drivers. AE bought Nick Mckinney's stock and designs a few years ago. Nick was much better on technical stuff than the business side. John may be a little better there, though maybe not his strongest suit either. It took me some time to get my drivers from Nick when he closed his business. John also took a while (and I had to remind him to charge me). The products from both were first rate, however.

On the spec side, the cones are a little heavier than Lynn considers optimal, IIRC. This should not be an issue for the dipole bass drivers.

Regarding the foam surrounds, I think that foam does have nice damping properties. The surrounds on my drivers are a coated foam. I've had them a few years now. I live on the coast and they get some sun exposure. I've seen zero degradation so far. If I notice any down the road, I'll have the surrounds redone. I see it as an extra maintenance issue, though not an onerous one.

Finally, John's is a small operation. My guess is that he would be willing to work with Lynn on spec's (different cone's, etc.) for small orders.

Sheldon

Hi Sheldon, Good to hear your drivers are still working well. You had ordered back during the period where everything was falling apart in my personal life with the loss of both my parents and some other stuff. I did try not to charge anyone for drivers until they were ready to ship. Now days we always make that a policy unless we know the drivers will be finished by the following morning to ship out.

Running the business is honestly not my strong point. It could be, however it's very difficult to do any one thing well when wearing so many hats.

Finally, I figured I might as well post the Dipole15 parameters here. Many people have asked for them lately from this thread so here they are with the dual 8ohm coils in parallel:

Originally posted by Etienne88 PHY-HP only sells driver that are pair matched with the following criteria:
- max tolerance on mobile equipment mass 0,1gr
- 0.1 Ohms on d.c. resistance
- 1Hz on resonance frequency

PHL gives tolerances for the resonance frequency and for the DC resistance of their drivers.

I'm not aware of any other brand that matches and/or gives tolerances for their units. (they might exist)

We haven't published these kinds of numbers, but they are specified with our vendors. For example a VC with a DCR of 3.2ohm would have a range from 3.1 to 3.3ohm, a variance of +/- 3%. Our IB drivers with an FS of 16Hz continually measure between 15.8Hz and 16.2Hz, a variance of +/- 1.25%. Our IB15's with 220gram spec'd Mms measure between 215-225 grams. , +/- 2.3%.

The somewhat "standard" in the industry is +/- 10%, however this gives quite a large range.

Quote:

Originally posted by Lynn Olson Well, Alexander of RAAL likes the PHY speakers and would like me to try them, so that counts for something. I've never heard them, just heard (several) recommendations for them.

The demands on the 10 to 15-inch speaker that meets the compression driver and horn system are very high: more than 96 dB/metre efficient, linear magnetic-system design (underhung voice-coil strongly preferred), low IM distortion particularly in the 500 Hz to 1.5 kHz range, and freedom from high-Q breakup modes at frequencies higher than 1.5 kHz.

It would be nice if it sounded good as well (subjectively agreeable colorations when auditioned full-range in an open baffle with no equalization.) I've been thinking about how nice it would be to have an Altec 414 fitted with a custom hemp cone by Tone Tubby, but frankly, that's further down the road and a project for another time. The 10-inch TAD I heard in the Audio Kinesis room at the last RMAF was very impressive, but I was saddened to hear that it is going out of production - it really looked, measured, and sounded like a superb driver. (For some reason, I've never warmed up to the TAD beryllium compression drivers, but I've always liked their midbass drivers. Go figure.)

So I don't know about the PHY's, honestly. At the current USD/Euro ratios, they are too expensive to experiment with - maybe I'll hear them somewhere in the USA. I've heard Altec 414's, 416's, 515's, TAD midbass drivers, and the Tone Tubby, and liked them all. I am not in the JBL camp, though - not my kind of sound.

Hi again Lynn,

It looks like the TD15M may be a good candidate for your high efficiency driver. The efficiency is just under 98dB 1w/1m. It does not use an underhung design, but has a tall 3/4" gap plate and a 4 layer flat aluminum coil with 3.3mm overhang. Looking at a BL curve of the driver the rated Xmax at 70% of the rest BL value is over 6mm and the curve shape is very broad, not peaky. These drivers are quite flat on axis up to well over 4KHz. Due to the full copper sleeve on the pole they are very low inductance and distortion is also very low. I'll post up the parameters from the old Lambda stuff since I don't have mine available here. This will give you a close idea:

Originally posted by augerpro Just when I buy an IB15 for testing you mention this Dipole15 I'm guessing by the inductance that this uses a copper plated pole like the IB15? What will the price be?

I was actually just looking at your driver tests yesterday. hopefully you will have good things to report about the IB15.

All of the drivers have more than just a copper plated pole. We actually had a custom made copper tube drawn to our specifications. +.003" -.000 were the tolerances on the OD of this tube as well as on the wall thickness. We then machine off the steel on the pole to within .003" tolerances and press on the copper with a special high temperature adhesive. This is a .025" thick copper sleeve. Plating would be no more than .003" thick and not nearly as effective.

Good to see that you are still going. These drivers are nice. Here's a raw unsmoothed nearfield measurement taken of my Apollo 15TDX. The measurement was taken at 15cm on a modified open baffle (sort of U-baffle, or a short open backed box). The lower end is crossed over at line level with a 80Hz second order transient perfect crossover. I don't have my system handy for full range measurements, or I would provide that.

This thread is huge and I am struggling to keep up with what is going on. Could you , in short, do a short resume on where your new plans lie at this moment in time.

Well appreciated!

Steve

No reason to read all that stuff, so here's a recap: I am designing a high-efficiency dipole in the 96~102 dB/metre range, with headroom and dynamics approaching horn systems. No drivers are going to be operated in regions of breakup or resonance, and they will be selected with a strong emphasis on smooth rolloffs out-of-band, in-band responses that require a minimum of equalization, and rapid settling times in the time domain.

Linkwitz and NaO are already doing a wonderful job with audiophile-efficiency systems, but that's not the direction I'm headed in, so I'm slogging through the pro-efficiency stuff, trying to uncover some of the harder-to-find specs like impulse response and CSD data from vendors that normally don't provide this kind of data.

The original concept, charming in its simplicity, was a high-efficiency coaxial augmented with one, two, or more medium-to-high Q bass-fill drivers. Instead of using Linkwitz's approach of equalization and high-power amplifiers, I'll be offsetting as much as possible of the baffle loss with increased cone area (and excursion capability). In practical terms, the "main" speaker is passively crossed over and powered by a high-quality Class A amplifier, while the bass-fill is equalized as necessary by line-level equalizers and separately powered.

The beautiful simplicity of the coaxial was regrettably spoiled by the not very smooth response of every coax I looked into. The separate bass and HF responses, although just barely acceptable when summed, were really pretty bad in every coax I came across. The more I found out about horns and waveguides, the more apparent it became that small deviations from the ideal profile (whatever that might be, much controversy there) exacted a terrible price in all domains - reflections in the time domain, narrowband spikes in directivity, and quite audible ripples in the frequency response. Yes, 12 and 15-inch Tannoys sound nice. They're not for sale from Tannoy, though, and it's way too much work to design a speaker around eBay unobtanium that's half-a-century old.

So I've settled on an "exploded-diagram" version of the Tannoy, with a medium-size horn or waveguide above, and 10~15 inch midbass driver below. In effect, an open-baffle variant of the original Jim Lansing Iconic speaker going back to the mid-Thirties.

But keeping to the original dictum of avoiding using drivers in regions where they are breaking up and/or entering regions of high distortion, the system is augmented on the low and high end. An array of bass-fill drivers (separately powered) offsets baffle loss (coming in below the baffle peak), while a supertweeter takes over in the region where the compression driver starts to go into breakup and the phase-plug emission becomes incoherent - this is typically 7~8 kHz for large-format drivers, 10~15 kHz for small-format drivers, and about 1.5X more for beryllium diaphragms.

Drivers on hand and planned to buy:

Supertweeter: Double-height RAAL tweeter with 100 dB/efficiency. Depending on the efficiency of the rest of the system, the double faceplate can be removed and a single RAAL used, dropping efficiency in half, or as another alternative, a different transformer can be used with a 4-ohm instead of the standard 8-ohm input.

HF: Altec 288, Great Plains Audio 399 fitted with the #23834 aluminum diaphragm, or Radian 745P. All of these are compression drivers with a 35mm exit, otherwise known as 1.4" large-format drivers. I'll probably be ordering either AH-340 or AH-550 Azurahorns from Australia - US-made wood horns appear to be many times more expensive, too much for what amounts to an experiment that may not turn out that well.

Midbass: One or two Altec 414's, 12" Tone Tubby's, or 18Sound 12NDA520's. No drivers with whizzers, these are impossible to equalize, and have limited power-handling.

Bass-Fill: Two or more Selenium 15PW-SLF's. This category is the most open of all - since they are going to be low-passed around 200 Hz or so, midrange quality isn't as critical as the others, and Xmax is much more important. Magnetar is thrilled with his array of 10" Madison guitar speakers, but I admit I am leary of speakers with no reliable Xmax specs and fairly low efficiency. They're cheap, though, can't argue with that. Not a fan of Eminence, would like to avoid them if possible.

Anyway, the whole thing is an experiment, and I have no idea if it will be a disaster or not. I've built a number of things - the Shadow Vector SQ decoder, various speakers at Audionics, the Ariel, and the Amity, Aurora, Raven, and Karna amplifiers, and some worked out well, and some didn't. Some turned out to reveal problems that were very difficult to solve (Aurora, some of my Audionics speakers), and others exceeded expectation (Shadow Vector, Ariel, Amity, and Karna). When you flip over rocks, no telling what you'll find underneath.

I am very very happy that Magnetar and other diyAudio forum members are building their own versions of high-efficiency high-headroom dipoles. The biggest - and quite valid - knock on dipoles has been woefully low power-handling, which is a shame considering the ability to reveal the sound of a driver without any cabinet coloration.

Dumping more power into dipoles when they're already using dynamically inadequate audiophile drivers just seems wrong in principle, just as it doesn't seem right to dump more power into compression drivers in the frequency range where distortion is increasing very rapidly. Much better to solve the problem in the acoustic domain, and increase headroom where necessary. There's no reason for the huge gulf between the professional and audiophile worlds - both have interesting technologies to offer each other.

P.S. My apologies for the snarky comment in the previous post, John J. It's good to see you here, and additional hard data is always, always welcome.

Originally posted by Lynn Olson
HF: Altec 288, Great Plains Audio 399 fitted with the #23834 aluminum diaphragm, or Radian 745P. All of these are compression drivers with a 35mm exit, otherwise known as 1.4" large-format drivers. I'll probably be ordering either AH-340 or AH-550 Azurahorns from Australia - US-made wood horns appear to be many times more expensive, too much for what amounts to an experiment that may not turn out that well.

Hello Lynn,

Did I misunderstand your previous post here in that you were considering a quartet of 18Sound 6ND410's as a direct radiator alternative to the CD + horn ?

If memory serves well you did discussed in the past some direct radiator alternatives for mids and the challenge in integrating them with the RAAL...

Thanks for that detailed response, it is really appreciated. So, you are going towards a compression driver to do the "big" part of the sound and woofers at the bottom end which will be biamped for the rolloff of 6db caused by the baffle. Whatever happened to the charming 15" wideband? I know you are telling me that they measure pretty badly(the coaxial and wizzer ones) but nonetheless, you were charmed by their magic...right?